charophytes A group of plants the members of which are usually regarded as algae, although they resemble bryophytes in the structure of the male gametes and in the presence of a sterile envelope enclosing the sex organs. Many species are heavily calcified. Fossil charophytes (from the Triassic onwards) are known only by their calcified oogonia, which often have a spiral ornament. Charophytes are aquatic, occurring primarily in fresh water, although some species are found in brackish water. Charophytes are sometimes included in a class within the division Chlorophyta and sometimes as a distinct division (Charophyta). Genera include Chara and Nitella. See also STONEWORT.

Charophyceae (charophytes) A class (in some classifications a division: Charophyta) of algae that in some ways resemble bryophytes (Bryophyta). They occur in fresh and brackish water and their calcified fructifications are ornamented with spiral striae. Neglected by geologists until 1959, they are now used as stratigraphic markers in Cenozoic strata. See GYROGONITE.

Charophyta See CHAROPHYCEAE.